My experience with Dungeons & Dragons;
Original D&D - I played a little D&D with friends when I was a kid, I don't think we ever quite had a real hold on the rules but it was a lot of fun and got me hooked for the rest of my life.
AD&D / 2E/2.5E - I played AD&D (then 2 & 2.5) while in High School back in late 80s/early 90s. After that I stopped playing any type of D&D for a long time due to RL and getting into MMORPGs.
D&D 3E - I've played one 3E game. I've also played various MMORPGs and other video game RPGs that used 3E style rules. I have the three core books and am familiar with the rules.
D&D4E - I've played some Encounters games using 4E rules and read through some of the PHBs. While the edition has a few things I like it is definitely my least favorite.
D&D Next - I have DMed an Encounters game/campaign with the latest D&D Next playtest rules. I have played in a Gameday event and a game on Roll20 using D&D Next rules also. I really enjoy this system and look forward to the full release.
(Pathfinder) - I've never played Pathfinder and just recently started reading the Core rulebook. I'd like to play this at some point.
I am also a big H.P. Lovecraft fan and would really like to try playing Call of Cthulhu sometime.